Peanut insect scouting is intensive

Matt Dischinger Farm Press Intern | Aug 16, 2006

Ron Weeks, an Extension entomologist and professor at Auburn University, has been working in the business of managing insects since 1975. But when he arrived at the Southern Peanut Growers Conference in Panama City, Fla., his goal was to raise awareness about insect management among peanut farmers.

“In recent years, there was a definite decline in interest in scouting peanuts,” Weeks says. “It's a very time and labor-intensive kind of procedure. We lost a lot of interest, so one of my goals with this presentation is to try to rekindle a little of that interest among our growers in actually doing insect management, which is more than just going out and finding insects and then deciding what you're going to spray them with.”

Weeks explained that insect management involves surveying, scouting and trapping. One method of control that Weeks encouraged was biological control, which involves using predators and parasites to eat away at the target pests. Weeks also advised using ecological control, like crop rotation and changing planting date, to control pests. He used the example of delaying planting dates to avoid thrips damage.

Both of those methods are more environmentally friendly than insecticide use, Weeks says.

“I'm not a tree-hugger entomologist like some folks are — if you talk about insecticides they'll throw you out of the room,” Weeks says. “But you usually want to wait until the last resort to use insecticides. If you can minimize insecticide use we can be in a better situation than we would if we just pulled the trigger with a broad spectrum of insecticides.”

The most common methods, Weeks says, are reactionary instead of preventive. Good scouting, which is somewhat difficult for peanuts, can end up saving the grower time and money throughout the season. For peanuts, scouts should keep an eye out for excessive defoliation, foliage feeders and soil insects.

Scouts should look for thrips early on in the peanut plant's life. Aphids have also been found during the early stages, Weeks says, but they are less common. Most of the foliage feeders are worms, such as wireworms and corn earworms.

Weeks says scouts should also look for burrower bugs, which could give off a smell similar to stink bugs. For burrower worms, treatment should be applied immediately when scouting reveals damage.

“I would encourage growers to start scouting peanuts and using more of these techniques in pest management to produce our peanuts,” Weeks says. “Obviously, this is a tough year. There are going to be some hard decisions to be made in the next few weeks concerning our peanut crop, but evaluating what's going on under the ground is the best way I know to determine what the potential is and what might be causing problems to our peanuts.”

Richard Sprenkel, an Extension entomologist and professor at the University of Florida, talked extensively about the two insects that are new and suspicious to the peanut crop.

The first is the three-cornered alfalfa hopper, which is most damaging to the stem of the peanut plant. The three-cornered alfalfa hopper has been studied significantly on soybeans, Sprenkel says, but not as much on peanuts. He said the insect pest most likely will follow the same pattern on peanuts as it has on soybeans.

Sprenkel says the pest caused serious damage to peanuts in some areas of the Southeast in 2005. He thinks it could be devastating in coming years to an already dwindling peanut crop.

According to the National Agricultural Statistics Service, approximately 1.3 million acres of peanuts were planted in 2006. This is a decrease of around 359,000 acres from 2005. The decrease could be attributed to the drop in price per pound from 2004 to 2005.

The other insect traveling somewhat under the radar that could become a more serious threat is the “quadrator” stink bug. It is slightly smaller than the brown stink bug and has two sharp points on the shoulders. This is a common sign of the spined soldier bug, which is a predator of other parasitic bugs.

The “quadrator” stink bug's disguise makes it hard to distinguish from the spined soldier bug, therefore making it harder to snuff out. This stink bug, like other stink bugs, is prevalent in mid- to late-August.

Sprenkel says neither of these bugs is currently obvious on the peanut insect control radar due to the relative anonymity. He does not expect this to last.

“We know enough about them to make me nervous,” Sprenkel says. “Both of the bugs fall under areas that need to be researched more on peanut plants.”